Artist Ben Wilson is lying on his side on the surface of London's famous Millennium Bridge, creating a painting on a piece of discarded chewing gum that has been discarded and smushed on the ground.

"The important thing is the gum is below the metal tread," said 60-year-old Wilson, dressed in a paint-daubed orange jumpsuit. "The beauty of it is they're all different shapes and sizes, so there's no conformity."

What most people actively avoid or don't see Wilson views as an opportunity to turn a tiny piece of discarded rubbish into something beautiful. It's also a way to delight passersby, enticing them to take a closer look underfoot.

"By painting a picture which is so small, those that see it then discover a hidden world beneath their feet," Wilson said. "If they look, then they see, so it's about perception."

Back in his north London studio, Wilson paints on the surface of a small mosaic tile, which will be part of a collection that he sticks on the walls of London's Underground train platforms, hidden in plain sight. The images are more personal than the chewing gum works, Wilson says, and represent an "intuitive visual diary."

"The pictures are a celebration of my life and those that I care dearly about ... they are (also) a process of visual inquiry – trying to make sense of the world," he said.

London-born Wilson was raised by artist parents and recalls working with clay from age three, with his first artist show at around 10 or 11 years old.

His artwork developed into sculpture and large pieces in the natural environment before his interest turned to rubbish and discarded items from a consumerist world, like chewing gum, which he's been painting for 19 years.

The top surface of the dried gum is not subject to local or national jurisdictions, creating a space where Wilson says he can paint without defacing public property.

"I found this little space where I could create a form of art where I could be spontaneous and do something which evolves out of the place in which it's created," Wilson said.

The artist has had much of his public street art removed by authorities – gum from the pavement or tiles from the Underground – but the hundreds of gum paintings on Millennium Bridge have been left untouched.